The present invention relates to a device for heating and ventilating large-area vehicles, such as buses, and comprises a housing having air entry and air exit openings, and at least one blower and one heat exchanger; the housing is arranged beneath the floor of the passenger area, and is provided with an open base surface, side walls, and end walls which at least partially converge towards the bottom; the current issuing from the blower proceeds at a relatively acute angle to the base surface of the housing, and also obliquely strikes the inlet side of the heat exchanger, the axis of through-flow of which, proceeding at right angles to the inlet and outlet sides, is inclined relative to the base surface at a greater acute angle than the current issuing from the blower; the portion of the base surface lying in the vertical projection of the outlet side of the heat exchanger forms the air outlet opening which leads to a distribution passage extending above the floor of the passenger area and in its longitudinal direction.
Such a device may be seen from German Offenlegungsschrift No. 28 43 746, which discloses a unit for heating and ventilating passenger areas in commercial vehicles. With uniform assembly, these units can be arranged at different locations in the commercial vehicle. The units are inexpensive in construction, and comprise at least one blower and one heat exchanger which are adapted to one another, and are arranged fixedly in relation to one another, in such a way that optimum possible efficiency is achieved irrespective of the nature of utilization. For this purpose the unit comprises a housing which is formed as a one-piece synthetic plastics trough with end and side walls converging from the open base surface to the bottom. The blower is arranged externally on the housing, and the mouth of its delivery pipe is inclined relative to the inlet side of the heat exchanger. The known device has a simple and compact assembly, so that it is suitable for widely differing utilization areas within the vehicle.
When the device is arranged beneath the floor of the passenger area, however, the problem arises that the externally situated blower has to be protected by additional measures, such as, for example, a wire mesh cage, in order to protect it within a luggage space against damage by luggage or--if as in town route buses there is no luggage space--to prevent the blower from being damaged by stones, water splashes, and the like. It is in fact known to arrange the heat exchanger and a blower beneath the floor of a passenger area within a closed housing the bottom of which has a repair access flap, but the housings themselves require considerable space since the heat exchanger and the blower are not arranged optimally in relation to one another. The air flow is deflected several times within the housing. Thus, optimum efficiency is not guaranteed. Moreover, a free space must be provided beneath the housing arranged beneath the floor of the passenger area; this free space corresponds at least to the height of the heat exchanger or the blower, so that these elements can be drawn downwards out of the housing and then removed laterally from, for example, the luggage space. Even if a sufficiently large free space is available, this work is expensive since the blower specifically, which needs frequent attention, is not directly accessible from outside.
In view of the above, it is an object of the present invention to make the blower of the device, which is arranged beneath the floor of the passenger area, accessible from different sides, especially from the exterior, without sacrificing the optimum efficiency of the device with respect to flow.